Did a Microsoft employee just inadvertently let the cat out of the bag? Posting to the company’s official Microsoft Imagine Cup Twitter account, a Microsoft rep confirmed that all Imagine Cup challenge finalists will receive Windows Phone 7.5 “Mango” handsets early this fall. Of course it wouldn’t be the first time Microsoft slipped this week. The post reads: “ImagineCup finalists ALL receive Windows Phone 7.5 Mango Release!! Each student will get the phone by September!” We doubt the tech giant plans to dole out pre-release devices, so it could be safe to assume the first batch of Mango phones will launch in late August or early September. Microsoft did not immediately respond to a request for comment.